JPH05185276A - Flux-containing al brazing sheet - Google Patents

Abstract

PURPOSE:To prevent sagging of a flux in the case of a large fluctuation in the coated. amt. of the flux or the large coated atm., to prevent the generation of a brazing defect by a binder and further to improve the corrosion resistance of a brazed produced in flux brazing of aluminum or the alloy material thereof by using the brazing sheet and to provide the flux-contg. Al brazing sheet for the above-mentioned purposes. CONSTITUTION:A skin material 2 as the brazing filler metal layer clad on one or both surfaces of a core material 1 contains prescribed ratios of Si and fluoride flux, further, contains one or >=2 kinds of Zn, Sn and In for imparting a sacrificial anode effect and consists of the balance aluminum and unavoidable impurities. The total of the elements excluding the flux and the fluoride flux are compounded at 99.9:0.1 to 70:30 ratio by weight and the density is >=90% of the theoretical value. This skin material is regulated to >=10mum thickness per one surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Al brazing sheet used for flux brazing of aluminum or its alloy material, and more particularly to a novel Al brazing sheet containing flux.

[0002]

2. Description of the Related Art Conventionally, in the case of flux brazing of aluminum or its alloy material, one or both of aluminum or its alloy material to be joined should be brazed on one or both sides of a core material in terms of manufacturing simplicity. It is performed by using an Al brazing sheet in which a skin material as a layer is clad. When brazing a flux using such a brazing sheet, the flux is adhered to the joint portion by applying a suspension or the like, and heating is performed in this state.

However, in such a conventional flux brazing using a brazing sheet, the flux has to be separately supplied to the joint, so that the work is troublesome. Moreover, there is a problem in that the amount of applied flux varies, and when the amount of applied flux is large, the flux drips during brazing to contaminate the brazing furnace.

The present invention has been made in view of the above technical background, and in flux brazing of aluminum or its alloy material, it is possible to prevent variations in the amount of applied flux and dripping of flux when the amount of applied flux is large. The present invention also aims to improve the corrosion resistance of the brazed product, and to provide a flux-containing Al brazing sheet for that purpose.

[0005]

In order to achieve the above-mentioned object, the present invention shows a brazing material on one or both sides of a core material (1) made of aluminum or an alloy thereof, as shown with reference to the drawings. Al clad with skin material (2) as a layer
In the brazing sheet, the skin material (2) is made of Si.
And fluoride-based flux, and further Zn, Sn, I
n, one or two or more, and the balance is aluminum and unavoidable impurities, and the Si content is 3 to 15 wt% with respect to the total content of elements excluding the fluoride-based flux, Zn.
The content is 0.1-5 wt% and the Sn content is 0.01-0.
5 wt%, the In content is 0.01 to 0.5 wt%, and the total of the elements excluding the flux and the fluoride-based flux are mixed in a weight ratio of 99.9: 0.1 to 70:30. And the density is 90% or more of the theoretical value, and the thickness of the skin material (2) is 10 μm on one side.
The gist is a flux-containing Al brazing sheet characterized by being specified to be m or more.

First, in the skin material (2), Al and Si function as a brazing material for joining aluminum or an alloy thereof, but the Si content relative to the total content of elements excluding the fluoride flux. If less than 3 wt% or more than 15 wt%, the liquidus temperature becomes high and brazing becomes difficult. Therefore, the Si content must be specified in the range of 3 to 15 wt% with respect to the total value of the elements excluding the flux. Particularly preferable Si content is 6
~ 12 wt%.

Zn, Sn and In in the skin material play a role of improving the corrosion resistance of the aluminum brazed product by making the electric potential of the brazing material base and the sacrificial anode effect. In terms of such effects, Zn, Sn, and In are all evaluated as equivalents, and it is sufficient if at least one of them is contained. Therefore, if the Zn content is less than 0.1 wt%, the Sn content is less than 0.01 wt%, and the In content is less than 0.01 wt% with respect to the total content of the elements excluding the fluoride-based flux, Poor effect. On the other hand, the Zn content exceeds 5 wt%, the Sn content exceeds 0.5 wt%, and the In content is less than 0.
Even if it exceeds 5 wt%, the sacrificial anode effect is saturated. Therefore, the Zn content is 0.1 to 5 wt% and the Sn content is 0.01 to 0.5 wt% with respect to the total content of the elements excluding the flux.
The In content should be specified to be 0.01 to 0.5 wt%, respectively. A particularly preferred content is Zn: 0.
5 to 2.0 wt%, Sn: 0.05 to 0.3 wt%, In:
0.03 to 0.1 wt%.

In addition to the above elements, Cu may be contained in order to improve the strength of the brazing material. The content of Cu is
0.05 to 5 wt% of the total value of elements excluding flux
It is good to set it as%.

The kind of the above-mentioned fluoride type flux is not particularly limited, and for example, potassium fluoride (KF).
And aluminum fluoride (AlF ₃ ) 45.8-5
Substantially complexed complex mixture having a eutectic composition of 4.2 or a composition range close thereto, KAlF ₄ , K ₂ A
lF _5, K ₃ may be used for complex product such as AlF _6.

The mixing ratio of the flux in the skin material (2) is
The weight ratio of this and the fluoride-based flux is 99.9: 0.1 with respect to the total of the elements excluding the fluoride-based flux.
It must be set to be ~ 70: 30.
This is because if the amount of flux is less than 99.9: 0.1 by weight, sufficient flux action cannot be exhibited and brazing becomes difficult. On the other hand, when the amount of flux exceeds 70:30, it becomes difficult to mix the flux with Al, Si or the like to solidify, and it becomes difficult to manufacture the skin material itself. A preferable mixing ratio of the total of elements excluding flux and the flux is 99.9: 0.1 to 8 by weight.
5:15, and particularly preferably 98: 2-9 by weight.
It is 0:10.

The above skin material (2) is generally prepared by mixing Al powder, Si powder, one or more kinds of Zn, Zn, and In powders with flux powder, and solidifying the mixture by hot pressing or the like. However, the density of the skin material is generally smaller than the theoretical value calculated from the densities of Al, Si, Zn, Zn, In, and the flux alone due to the residual internal air. Therefore, in the present invention, the density of the skin material must be 90% or more of the theoretical value. If the density of the skin material is less than 90% of the theoretical value, there is a risk that the pores are connected to the inside but become brittle, although Al, Si, etc. and the flux are solidified, and then the core material (1) Clad processing with and is difficult, and it is practically impossible to make a brazing sheet. Particularly preferably, the density of the skin material is 95% or more of the theoretical value.

A preferred specific method for producing the skin material (2) is as follows. That is, first, as a starting material, Al
Powder, Si powder, one or more kinds of Zn, Sn, and In powders and flux powder are prepared. These powders have an average particle diameter of 44 μm or less for Al powder, an average particle diameter of 5 μm or less for Si powder, and Zn, Sn, I
It is preferable that the n powder and the flux powder have an average particle diameter of 44 μm or less and 30 μm or less, respectively. The starting materials are not necessarily Al, Si, Z.
It is not necessary to use n, Sn, and In alone, but they may be used in the form of Al—Si alloy powder or an alloy containing Zn or the like.

Next, the above powders are mixed so as to have the above-mentioned predetermined mixing ratio, and then filled into a container such as an Al can, and then the inside of the container is degassed to 1 mmHg or less, and then hot pressing or the like. To heat and compact.

Next, after removing the outer can body of the obtained thermocompression molded body by cutting, the molded body is extruded to obtain a plate-shaped skin material.

The skin material (2) is clad on one or both sides of the core material (1) to form a brazing sheet, and the thickness of the skin material (2) must be 10 μm or more on one surface. This is because if the thickness of the skin material is less than 10 μm, the brazing material required for brazing will be insufficient, making brazing difficult.
It is particularly preferable to secure the thickness of the skin material on one side of 20 μm or more.

The composition of the core material (1) is not particularly limited, and the material used as the core material of the conventional aluminum brazing sheet may be used. For example, A
A 3000 series aluminum alloy such as 3003 or 3005, or a 6000 series aluminum alloy such as A6951 may be used.

The brazing sheet may be manufactured by pressing the plate-shaped core material and the plate-shaped skin material obtained above in a hot state, and if necessary, further hot rolling or cold rolling. ..

[0018]

Embodiments of the present invention will be described below.

Aluminum powder having a purity of 99.5% (average particle size 44 μm), Si powder (average particle size 5 μm), Zn powder (average particle size 44 μm), Sn powder (average particle size 40 μm)
m), In powder (average particle diameter 40 μm), and fluoride flux powder (average particle diameter 30 μm). A eutectic composition of KF and AlF ₃ was used as the flux. Next, the above powders were mixed uniformly at room temperature by changing the mixing ratio so as to have the respective ratios shown in Table 1 below, and then the respective mixtures were mixed with each other having a diameter of 3 inches and a length of 200 mm.
Each can was filled in the air.

Next, each Al can of the upper atmosphere was placed in a furnace at 500 ° C., and the inside of the Al can was vacuum degassed to 1 mmHg or less.

Then, the Al can was heated to 480 ° C., and then hot-pressed using a hot press at a maximum pressure of 400 tons, and the length of the formed product was 110 mm.

After that, Al adhering to the outside of the molded body
After removing the can body by cutting, the temperature is set to 500 by a hot extruder.
It was extruded at a temperature of ° C into a flat plate having a thickness of 3 mm and a width of 30 mm.
Table 1 shows whether or not extrusion molding is possible at that time.

With respect to the plate-like skin material that was extrudable as described above, its density was determined and compared with the theoretical density calculated based on the starting material. The results are shown in Table 1.

[0024]

[Table 1] Then, the plate-like leather material that was extrudable as described above was formed into an A3 sheet having a thickness of 20 mm, a width of 50 mm and a length of 200 mm.
Both sides of a core material made of an extruded plate made of 003 Al alloy were pressed against each other while hot.

Then, cold rolling is performed to obtain two kinds of brazing sheets having a thickness of 1 mm (skin material one side thickness: about 83 μm) and a thickness of 0.1 mm (skin material one side thickness: about 8.3 μm). I made it.

Next, each of the brazing sheets obtained above was cut into a length of 50 mm and a width of 30 mm.
And these cut pieces are 50 mm long × 30 mm wide ×
A reverse T-joint was formed by vertically arranging it on an A3003Al alloy plate having a thickness of 1 mm, and this was brazed by heating it at 600 to 620 ° C for 10 minutes both in N2 atmosphere and air. The attachability was evaluated. In addition, No2, 4, 5, 7,
10 brazing products (Brazing sheet heat 1.0m
m)), the corrosion state of the core material was examined when the salt spray according to JIS Z2371 was applied for 1000 hours. The results are shown in Table 2.

[0027]

[Table 2] From the results shown in Table 2, it was confirmed that the flux-containing Al brazing sheet according to the present invention can exhibit excellent brazing property without additional application of flux, and can also improve the corrosion resistance of the brazed product. It was possible. Further, when the brazing sheet has a thickness of 0.1 mm, one side of the brazing filler metal layer has a thickness of less than 10 μm, and thus sufficient brazing cannot be performed due to insufficient brazing filler metal.

[0028]

[Function] During brazing, the surface oxide film on the joint is removed by the flux mixed inside the skin material, the brazing material spreads wet, and the brazing joint is as good and strong as when the flux is separately applied. To be achieved. Therefore, it is no longer necessary to apply the flux separately. In addition, the corrosion resistance of the brazed product is improved by the sacrificial cathode effect of one or more of Zn, Sn, and In added to the skin material.

[0029]

According to the present invention, the skin material as the brazing material layer of the Al brazing sheet contains Si and a fluoride-based flux, and further contains one or more of Zn, Sn and In. , The balance consisting of aluminum and unavoidable impurities, the Si content is 3 to 15 wt%, the Zn content is 0.1 to 5 wt%, and the Sn content is 0.01 with respect to the total content of the elements excluding the fluoride-based flux. ~ 0.5 wt%,
In content is 0.01 to 0.5 wt%, and the total of elements other than the flux and the fluoride-based flux are mixed in a weight ratio of 99.9: 0.1 to 70:30,
In addition, since it is formed of a material having a density of 90% or more of the theoretical value, and the thickness of the skin material (2) is specified to be 10 μm or more on one side, The flux of this exerts the effect sufficiently,
Good brazing can be performed without separately supplying flux. Therefore, the flux applying step can be eliminated, the joining work efficiency can be improved, and the productivity of the aluminum brazed product can be improved.

In addition, since the amount of flux mixed in the skin material is regulated within a certain range, there is no fear of variations in the amount of flux as in the case of applying the flux, and the flux action is surely exhibited. In addition, it is possible to eliminate the inconvenience that the inside of the brazing furnace is contaminated due to too much flux coating amount.

Moreover, good brazing can be performed not only in an inert gas atmosphere but also in the atmosphere,
Brazing equipment can also be simple.

A predetermined amount of Zn, Sn, In is used as the skin material.
1 or 2 or more thereof are added, the corrosion resistance of the aluminum brazed product can be improved by the sacrificial anode effect.

[Brief description of drawings]

FIG. 1 is a sectional view of a brazing sheet according to the present invention.

[Explanation of symbols]

 1 ... Core material 2 ... Leather material

Claims (1)

[Claims] 1. A skin material (2) as a brazing material layer on one or both sides of a core material (1) made of aluminum or an alloy thereof.
In the Al brazing sheet in which is clad, the skin material (2) contains Si and a fluoride-based flux, further contains one or more kinds of Zn, Sn and In, and the balance aluminum and inevitable impurities, Si with respect to the total content of elements excluding fluoride flux
Content is 3 to 15 wt%, Zn content is 0.1 to 5 wt%,
The Sn content is 0.01 to 0.5 wt% and the In content is 0.
01 to 0.5 wt%, and the total weight of the elements excluding the flux and the fluoride-based flux is 99.9:
The material is blended in a ratio of 0.1 to 70:30 and has a density of 90% or more of the theoretical value, and the thickness of the skin material (2) is specified to be 10 μm or more on one side. A flux-containing Al brazing sheet, comprising: